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UM0438

Simplified mnemonics for VLE instructions

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A.5

Simplified mnemonics that incorporate the BO32 and BO16

operands

The mnemonics in Table 18 allow common BO32 and BO16 operand encodings to be

specified as part of the mnemonic, along with the set link register bit (LK). There are no

simplified mnemonics for unconditional branches, branch to link register, and branch to

count register. For these, the basic mnemonics e_b, e_bl, se_b, se_bl, se_blr, se_blrl,

se_bctr, and se_bctrl are used.

Table 19 shows the syntax for basic simplified branch mnemonics

The simplified mnemonics in Table 18 that test a condition require a corresponding CR bit

as the first operand (as the examples in Section A.5.1: Examples that eliminate the BO32

and BO16 operands below illustrate). The symbols in Table 17 can be used in place of a

numeric value.

A.5.1

Examples that eliminate the BO32 and BO16 operands

The simplified mnemonics in Table 18 are used in the following examples:

Table 18.

Branch simplified mnemonics

Branch semantics

LR Update Not Enabled

LR Update Enabled

e_bc

se_bc

e_bcl

Branch if condition true

e_bt

se_bt

e_btl

Branch if condition false

e_bf

se_bf

e_bfl

Decrement CTR, branch if CTR

≠ 0(1)

Simplified mnemonics for branch instructions that do not test CR bits should specify only a target.

Otherwise, a programming error may occur.

e_bdnz

—

e_bdnzl

Decrement CTR, branch if CTR = 01

e_bdz

—

e_bdzl

Table 19.

Branch instructions

Instruction

Standard mnemonic

Syntax

Simplified

mnemonic

Syntax

Branch

e_b (e_bl)

se_b (se_bl)

target_addr

N/A, syntax does not include BO32 or

BO16

Branch Conditional

e_bc (e_bcl)

se_bc

BO32,BI32,target_add

BO16,BI16,target_add

e_bx(1) (e_bxl)

se_bx1

BI32(2),target_addr

BI16 2,target_addr

Branch to Link

se_blr (se_blrl)

—

N/A, syntax does not include BO32 or

BO16

Branch to Count

se_bctr (se_bctrl)

—

N/A, syntax does not include BO32 or

BO16

x stands for one of the symbols in Table 14 where applicable.

BI32 or BI16 can be a numeric value or an expression as shown in Table 17..

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